The Lung Surfactant and Immune System Response to Intratracheal Administration of “Empty” Liposomes

Abstract

After intratracheal administration of “empty” lecithin-cholesterol liposomes to rats it was found out twofold enhancement of the surfactant content with maximum on the 2nd-3rd day and with normalization to the control level by the 7th day. Phagocytic index of the alveolar macrophages was also increased. It was shown the change of the blast-transformation reaction of bronchoalveolar lavage and blood lymphocytes. Immune complexes content in bronchoalveolar lavage at different period of time after liposomes administration increased 1.5-2-fold. The natural killers (NK) activity of cells obtained from bronhoalveolar lavage and blood was enhanced 10 times and 2 times respectively. It is supposed that enhancement of lung surfactant phospholipid content is caused by substrate stimulation of type II alveolocytes activity. The stimulation of immunocompetent cells might be connected with imitation of bacterial attack by liposomes with proteins adsorbed on their surface.